SamizdatMath

FACT: Students need more practice solving subtraction problems. FACT: This collection has lots of subtraction problems. FACT: Not all subtraction problems are the same: some are "take away," some are "let's compare one with another," some are "I have something and took away this, now I have this...." This is a collection of over 200 different "Busy Bee Hive" puzzles where students practice subtraction in a context that is fun and thoughtful. That is, yes, they get lots of opportunities to do "ta

Do you want to know what the problem is with all that math you think you're "teaching?" It's missing something, and no, it's not "standards," or "aims" or "concision" or cryptocurrency. No, it's missing something far more important. AND, would you like to use a measurement system used by 98% of all the countries in the world? Your math is missing "ambiguity." And the metric system! Let's look at how your textbook is probably teaching area and perimeter. It probably states the definition, and th

BY SPECIAL REQUEST! For those of you who enjoyed Coin KenKen and Ultra Coin KenKen, I know bring you TURBO COIN KENKEN: a 5 x 5 grid with half dollars, quarter dollars, dimes, nickels and pennies to arrange on a grid so that the values equal to the shaded in area, and all coins appear once in each column and row. 5 puzzles, 5 answer sheets. Happy Problem Solving to All!

Do you want to know what the problem is with all that math you think you're "teaching?" It's missing something, and no, it's not "standards," or "aims" or "concision" or cryptocurrency. No, it's missing something far more important. Your math is missing "ambiguity." Let's look at how your textbook is probably teaching area and perimeter. It probably states the definition, and then gives a bunch of cruddy problems where you calculate the area and perimeter of a bunch of rectangles and then moves

Back in the 1980s (before most of you were born), the A & W hamburger restaurant chain tried to go head to head with McDonalds' new "quarter pounder" by creating and marketing a "⅓ pound hamburger." It was a spectacular flop. A research company hired to find the source of the problem found out that half of the people surveyed thought that there was less meat in a ⅓ lb. burger than a ¼ lb. burger because, well, "3 is less than 4." The burger was renamed the "Big Papi" and continued to be sold b

This is NOT your typical "is this a prime or composite number, and if it is composite, show the prime factor" exercise. No, this is an activity that actually demonstrates how figuring out prime factors is linked to encrypting information securely. If you know about the Russian Postal Service puzzle, then you'll appreciate this. There are 10 different puzzles, and then a "DIY" where your students can make their own "prime puzzlers" to share with one another. If they're really good, send them to

Okay, you're teaching your kids how to do two and three column addition.... WHAT A SNOOZE! I promise you, this is going to be fun! Here's how it works: you've taught your students about regrouping/carrying in multi-column addition, and they've done a few problems and you want them to have a little more experience with it while doing some deep thinking. This is the activity for you! This collection of "ink blot addition puzzles" will engage your students in a completely different way, because

There is no cutesy kids or animals in this activity; it focuses on the math without distraction. This is an activity where children practicing using the "count up" and "count down" activity to make change from whole dollar amounts ($1, $2, $3, and in denominations up to $20.) It is designed to replicate the "real life" experience of giving change when the buyer has a non-whole dollar total. It also gives students practice in making change using coins, or combinations of bills and coins. The goa

Here's the problem: There are 100 seats on an airplane and 100 people waiting to get on. The first person loses their boarding pass, so they take a random seat on the plane. If the next person finds their seat occupied, they take another random seat. If their seat is free, they sit in it. Question: What is the probability that the 100th person on the plane will sit in their assigned seat? Oh, sure, you can look up the answer and come up with some convoluted or excessively mathematical explanati

This is the one and only collection of "MadHard" 'puzzlas' that I have been collecting, editing and finally, answering for more than a decade. Each one is designed to test the mathematical meddle of your kids, from 3rd through 8th grade. Are they hard? Oh, some are sooooo hard that they even stumped mathematicians! Others are a little less hard, but they're all pretty unique and fun and the contexts are nothing like you've ever seen before. Here are some examples: • A cute baby dressed as a tac

This is a seven part investigation into the carbon footprint of different kinds of food and diets. Investigation #1: What We Emit When We Eat: This is a list of 20 different foods, including meats, dairy, vegetables and grains and the amount of carbon released during their production. Students calculate the equivalent in miles driven by a car, as well as the amount of carbon released per ounce. Investigation #2: Students investigate the carbon footprint of three different meals. The first is a s

This is an approach to teaching the geometric concepts of complementary, supplementary and exemplary (also known as conjugal) angles through groupwork and problem solving using non-standard examples. This makes this activity different from anything else you’re likely to see anywhere. Why is this? Because most curricula treat this important topic as one where students see some examples, solve some lame-o problems related to them, and then more on. No thought is given about how to make this intere

This is a collection of 36 factor riddles to help your students prepare to factor quadratic equations.

Here's another mathematics investigation straight out of the SamizdatMath laboratory. Yes, the same place which brought you " How to Hack Your Burrito," " What's the Best Way to Fit a 15' Fishing Pole in a 10' Box?" AND "WTF is Survivor Bias and Why Should I Care About It?" now brings you a complete investigation into the age old problem "what's the fastest way to cook 3 steaks in a pan that only holds 2 at a time?" This is a problem that has been circulating around, and it has a fun solution,

This is a collection of 30 different three-clue puzzles that lead to a solution that can be made on the geoboard using a single rubber band. Actually, there are some that can be solved, but not on a geoboard, and there are some that can't be solved at all (for example, making an equilateral triangle with a right angle.) The goal of these puzzles is for your students to take the descriptions of a shape and tun it into a visual representation (using a geoboard) and then record that solution and th

This is an activity that investigates the issue of gerrymandering from many different sides; it is not designed to indoctrinate your students into the idea that gerrymandering (or drawing any kind of electoral districts) is "good" or "bad." Rather, it looks at the idea at what are different forms of "fair" representation. By re-framing this as a Dingo vs. Raccoon issue, we can rise above partisan politics and see this as a philosophical argument about what "democracy" really looks like. The firs

First of all, it should not be called the "Pythagorean Theorem," because Pythagoras had nothing to do with inventing or discovering it. The Chinese knew about it hundreds of years before, and the Mesopotamians? Like 1300 years before! Zip Zap.... Okay, this is a really REALLY cool activity that uses the "Pythagorean" Theorem to solve a very important question: how can you ship an 11 foot fishing pole, when the shipping box can't be any more than 10 feet in length? Take some time to scratch you

Here’s a nice little “take home” activity that develops both visual spatial skills, mathematical vocabulary AND it's really fun! Here’s how it works: print out the puzzles and challenge booklet on card stock (or laminate before cutting out...) and have your kids cut them out. The kids cut out the “clue cards” and have kids write clues about the different puzzles. Then they can share their cards and look at one another’s clue cards, find the shape it is describing and use the puzzle pieces to “s

This is an old problem I saw almost 20 years ago: suppose you took two dice and rubbed off the pips (dots) from the faces, and instead put on numbers. How would you number it in such a way that you can roll the two dice and make all the numbers from 1 to 36? This is a wonderful problem to study combinations, patterns and general problem solving techniques. It is "hard" in that you can't calculate your way through it, and the solution evolves slowly as you work through the problem. But the soluti

This is an activity that analyzes the legitimacy of the "electoral college" system of voting in the United States, and whether it really is based on "one person, one vote." It uses census data from 2010 to show that when it comes to influence on presidential elections, states with smaller populations have a disproportional effect on the outcomes. The activity begins by explaining the workings of the electoral college system, describing how each state gets one elector for each house member, plus